This invention relates generally to exercise treadmills and, more particularly, to treadmills having an endless belt which is entrained around a pair of spaced rollers, and which has an upper reach on which a user can walk or run.
Typically, exercise treadmills include a continuous or endless belt which is entrained about a pair of spaced rollers. The belt has an upper reach which extends over a support deck which engages an underside of the upper reach for supporting a user while walking or running on the upper reach of the belt. The support deck and rollers are typically secured to a base or frame with one of the rollers near a front end of the treadmill and the other of the rollers near a rear end of the treadmill.
A problem with some prior art treadmills is that the belt supporting structure or support deck is too rigid and unyielding. While a certain amount of deck rigidity is necessary for the belt supporting structure to properly support the user while he or she walks or runs on the treadmill, rigid and unyielding support decks may be uncomfortable for the user and can be potentially damaging to the joints and tendons of the user, especially when the treadmill is used over long periods of time. These problems have been addressed in some prior art treadmills which incorporate shock absorption means that provide a softer walking or running surface.
Another problem with many prior art treadmills is that the degree of resiliency or shock absorption of the support deck is generally a constant that does not necessarily suit all users nor all uses of the treadmill. Different levels of "energy return" (springiness or resiliency) and/or impact cushioning may be desirable during walking or running, as well as for other reasons such as medical rehabilitation. Also, the same treadmill is often shared by multiple users that may have vastly different weights and exercise abilities. Thus, there is a need for a treadmill belt supporting structure that permits the user or users to selectively adjust the degree of resiliency or "energy return" of the support deck, as well as the degree of impact cushioning or shock absorption.